scholarly journals Modeling, Identification, and Control of a Discrete Variable Stiffness Actuator (DVSA)

Actuators ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 50 ◽  
Author(s):  
Irfan Hussain ◽  
Ahmad Albalasie ◽  
Mohammad I. Awad ◽  
Dongming Gan
Keyword(s):  
Variable Stiffness ◽  
Torque Control ◽  
Discrete Variable ◽  
Linear Quadratic ◽  
Control Schemes ◽  
Variable Stiffness Actuation ◽  
Working Principle ◽  
Variable Stiffness Actuator ◽  
And Control ◽  
Future Work

A branch of robotics, variable impedance actuation, along with one of its subfields variable stiffness actuation (VSA) targets the realization of complaint robotic manipulators. In this paper, we present the modeling, identification, and control of a discrete variable stiffness actuator (DVSA), which will be developed for complaint manipulators in the future. The working principle of the actuator depends on the involvement of series and parallel springs. We firstly report the conceptual design of a stiffness varying mechanism, and later the details of the dynamic model, system identification, and control techniques are presented. The dynamic parameters of the system are identified by using the logarithmic decrement algorithm, while the control schemes are based on linear quadratic control (LQR) and computed torque control (CTC), respectively. The numerical simulations are performed for the evaluation of each method, and results showed the good potentialities for the system. Future work includes the implementation of the presented approach on the hardware.

scholarly journals Simultaneous position and stiffness control of a revolute joint using a biphasic media variable stiffness actuator

2019 ◽  
Vol 1 (2) ◽  
pp. 80-97
Author(s):  
Jesus H Lugo
Keyword(s):  
Control Method ◽  
Variable Stiffness ◽  
Industrial Processes ◽  
Revolute Joint ◽  
Additional Information ◽  
Physical Prototype ◽  
Stiffness Control ◽  
Variable Stiffness Actuator ◽  
Control Fluid ◽  
And Control

Safe interactions between humans and robots are needed in several industrial processes and service tasks. Compliance design and control of mechanisms is a way to increase safety. This article presents a compliant revolute joint mechanism using a biphasic media variable stiffness actuator. The actuator has a member configured to transmit motion that is connected to a fluidic circuit, into which a biphasic control fluid circulates. Stiffness is controlled by changing pressure of control fluid into distribution lines. A mathematical model of the actuator is presented, a model-based control method is implemented to track the desired position and stiffness, and equations relating to the dynamics of the mechanism are provided. Results from force loaded and unloaded simulations and experiments with a physical prototype are discussed. The additional information covers a detailed description of the system and its physical implementation.

A Stochastic Regulator for Integrated Communication and Control Systems: Part II—Numerical Analysis and Simulation

1991 ◽  
Vol 113 (4) ◽  
pp. 612-619 ◽  
Author(s):  
Luen-Woei Liou ◽  
Asok Ray
Keyword(s):  
Control Systems ◽  
Numerical Procedure ◽  
Linear Quadratic Regulator ◽  
State Feedback Control ◽  
Control Law ◽  
Linear Quadratic ◽  
Simulation Experiments ◽  
Integrated Communication ◽  
And Control ◽  
Future Work

A state feedback control law has been derived in Part I [1] of this two-part paper on the basis of an augmented plant model [2, 3, 4] that accounts for the randomly varying delays induced by the network in Integrated Communication and Control Systems (ICCS). The control algorithm was formulated as a linear quadratic regulator problem and then solved using the principle of dynamic programming and optimality. This paper, which is the second of two parts, presents (i) a numerical procedure for synthesizing the control parameters and (ii) results of simulation experiments for verification of the above control law using the flight dynamic model of an advanced aircraft. This two-part paper is concluded with recommendations for future work.

Design and Control of a Passive Noise Rejecting Variable Stiffness Actuator

2018 ◽  
pp. 235-262
Author(s):  
Luca Fiorio ◽  
Francesco Romano ◽  
Alberto Parmiggiani ◽  
Bastien Berret ◽  
Giorgio Metta ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Variable Stiffness Actuator ◽  
Passive Noise ◽  
And Control

scholarly journals Decentralized Control for Scalable Quadcopter Formations

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Qasim Ali ◽  
Sergio Montenegro
Keyword(s):  
Position Control ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Time Duration ◽  
Control Effort ◽  
Ground Station ◽  
Model Following ◽  
Control Scheme ◽  
Control Schemes ◽  
And Control

An innovative framework has been developed for teamwork of two quadcopter formations, each having its specified formation geometry, assigned task, and matching control scheme. Position control for quadcopters in one of the formations has been implemented through a Linear Quadratic Regulator Proportional Integral (LQR PI) control scheme based on explicit model following scheme. Quadcopters in the other formation are controlled through LQR PI servomechanism control scheme. These two control schemes are compared in terms of their performance and control effort. Both formations are commanded by respective ground stations through virtual leaders. Quadcopters in formations are able to track desired trajectories as well as hovering at desired points for selected time duration. In case of communication loss between ground station and any of the quadcopters, the neighboring quadcopter provides the command data, received from the ground station, to the affected unit. Proposed control schemes have been validated through extensive simulations using MATLAB®/Simulink® that provided favorable results.

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